Am in the process of building a new PC ( thanks to the TR Sweet Spot recommendations) however I have gone the Xeon E3 series route for my CPU.I had originally ordered the E3 1230v2 as it is explicitly stated in Ark that it is compatible with the Intel Z77 Spur Lake mobo which I have also ordered.They (the etailer) informed me that this CPU was out of stock and offered the step up CPU above.

Looking at Ark however, the 1240 is NOT listed in the compatible CPU list,while even the higher end CPUs in this series are.

Will this CPU work in this mobo? The custom builders are, ahem , building it for me and they said they will test and hold thumbs, but I'm pretty confident it should work if the BIOS is updated.Am I correct in this assumption or should I just cancel the Xeon order and grab a 3770k and not worry and delay my build further?

If the chip stepping is the same, it will certainly work... but why are you going for a Xeon in a z77 board?4C8T for a better price than a 3770K: good justificationBetter performance than 3570K: not really, a 3570K will clock a lot higherECC RAM: doesn't work in Z77, just get a 3770k

I would also mention 3770k lacks VT-d if OP uses it, and intel claims some of their Z77 boards DO support it. (used to be only sure bet were server and Q series)Equivalent E3 xeons are usually cheaper if you don't have microcenter nearby.

It will work. I just got my best friend to buy one and we built it the other day, it runs amazingly. You wont need ECC RAM so you'll be fine. The i5-3550k is definitely comparable however. If you need 8 cores go with the Xeon, if you don't save the few extra bucks and go with the i5.

I'd be surprised if it didn't work. I have a 1230 v2 in my z77 board at work. But it is very true that hyperthreading delivers far less that real cores. My Xeon 1230 v2 is just 20% faster at rendering than the i5 3570. An i5 3570K could easily catch up to the Xeon with a little bit of overclocking. As others have said, the i5 3570K is a better buy unless you really need the extra threads. Or ECC memory, which won't work in a z77 board - you need a C204 or C206 board for that.

Oh, and if you can afford it and really do need the extra threads, the i7 3770K is definitely the better choice as it will give you the additional threads and the ability to run an overclock. A modest overclock (25%-30% is very modest with Ivy Bridge) will make the extra cost worth it. You can't overclock the Xeons other than setting all cores to run at the max turbo speed. The i7 3770K will clock far beyond that.

tl;dr: unless you *really* need the threads or else you need ECC memory, give the Xeon a pass.

Not looking to over-clock CPU at all, just looking at a good all-round system for various tasks.The price difference between the 1240 and the 3770k here in South Africa is around R700 or roughly $90 !The Rand-Dollar exchange rate fluctuates daily down here so any delay can be costly ( sitting at around R9 to $1) Ouch!I have rather spread this difference of the total budget into an Intel 335 SSD for OS and the WD red 3TB for storage.Will let you know what the system builders say.

E3 1240v2 uses the same silicon as its desktop counterpart, so it will work with the same chipsets. The only caveat is if you want to use ECC on the Xeon chip, you'll need a motherboard with ECC support.